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On 10/13/17 7:05 AM, Mr. Luddite wrote:
On 10/13/2017 5:32 AM, John H wrote: On Thu, 12 Oct 2017 17:48:36 -0400, "Mr. Luddite" wrote: On 10/12/2017 5:05 PM, Keyser Soze wrote: On 10/12/17 4:53 PM, wrote: On Thu, 12 Oct 2017 16:42:10 -0400, wrote: I was curious so I looked it up.Â* A fully dressed 454 with cast iron heads weighs 685 lbs from the factory.Â* A CumminsÂ* 5.9L diesel by comparisonÂ* is 1200 lbs or 515 lbs heavier.Â* Twins would mean a weight difference of over 1,000 lbs.Â* That's quite a bit, even for a 39' boat. Major difference is:Â* The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year)Â* while the diesel CumminsÂ* develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. === I believe the extra torque is mostly a result of the higher compression ratio in a diesel.Â* The higher ratio effectively increases the duration of the power stroke compared to a gas engine. I thought it was the result of a combination of factors, including higher compression ratio, more heat content of the fuel, higher turbo boost pressure, and greater heat content of the fuel, and continuous pushing of that fuel into the cylinders. Probably all you mentioned ... oh and also the greater heat content of the fuel in case you forgot.Â*Â* :-) He probably missed that with his cut'n'paste. yup. Shouldn't you boys be telling us to give Trump a chance? |
#3
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Keyser Soze wrote:
On 10/13/17 7:05 AM, Mr. Luddite wrote: On 10/13/2017 5:32 AM, John H wrote: On Thu, 12 Oct 2017 17:48:36 -0400, "Mr. Luddite" wrote: On 10/12/2017 5:05 PM, Keyser Soze wrote: On 10/12/17 4:53 PM, wrote: On Thu, 12 Oct 2017 16:42:10 -0400, wrote: I was curious so I looked it up. A fully dressed 454 with cast iron heads weighs 685 lbs from the factory. A Cummins 5.9L diesel by comparison is 1200 lbs or 515 lbs heavier. Twins would mean a weight difference of over 1,000 lbs. That's quite a bit, even for a 39' boat. Major difference is: The 454 develops 450-500 lb-ft of torque at 3200 RPM (depending on year) while the diesel Cummins develops peak torque of 610 lb-ft at 1600 RPM The extra torque probably comes from the longer stroke in the diesel. (4.0" vs 4.75") They make gasoline engines "square" or even over bore to reduce the reciprocating forces of a longer stroke for a given displacement It lets them run at higher RPMs. === I believe the extra torque is mostly a result of the higher compression ratio in a diesel. The higher ratio effectively increases the duration of the power stroke compared to a gas engine. I thought it was the result of a combination of factors, including higher compression ratio, more heat content of the fuel, higher turbo boost pressure, and greater heat content of the fuel, and continuous pushing of that fuel into the cylinders. Probably all you mentioned ... oh and also the greater heat content of the fuel in case you forgot. :-) He probably missed that with his cut'n'paste. yup. Shouldn't you boys be telling us to give Trump a chance? Shouldn't you be posting original thoughts? Anyone can search the internet for whatever fits their agenda. |
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